In its standard form Sahidic, it consists of the 24 Greek letters plus G signs borrowed from the Ancient Egyptian Demotic script that stand for coptic sounds not symbolized in Greek; The Story of Writing

George Bernard Shaw left money in his will to design a rational of at least 40 letters: talls, deeps, shorts, and compunds. The name of each letter is given beneathit, and its sound is printed in bold type; The Story of Writing